GalaxyGael

Lovely image and I guess your skies are B4 or better when this was taken? Fast scopes and latest gen backlit CMOS OSC can be a 'gateway drug'. Quite something for 3 minutes straight out of the camera. I just moved from f/6 to f/2.8 in Bortle 6 and it made me smile.

I was looing at these when I was talking to a colleague to who has ABB robotic arms in their labs (like in the car making industry) that have astonishing levels of precision. These Rainbow astro and Hobym look like a variation of this tech. How is the guiding and PEC, given strain wave harmonic drives can have large amplitude long period error. OK in general use? Industry that use such encoder and drives have mastered PEC, but not yet in the mount makers. They look amazing for their size. I saw a demo where someone held onto the end of a hobym, hanging freely, and it lifted the person without any strain.

The GEM 45 is great, and my guiding is between 0.37 and 0.65 depending on seeing. I have pulled it completely apart to fix a belt after it got squashed causing huge guiding excursions every 12 or so minutes, and very easy to service if ever needed to. Handles the scope perfectly, and can handle a lot more for its size, I think about 20 kg in addition to a 5kg counterweight. I have the unusual GEM45G, with slightly off red RA axis (they are normally the same ZWO-type red, but not mine). I has the GEM45G saddle, but without the iguider built in. So it has both vixen and losmandy options, 2 x 3A 12 V power outlets where my ASI2600 plus in, the saddle USB for the guidescope etc. So the ioptron has just one cable to the laptop. The standard GEM45 doesn't have all these, fyi. There are encoder variants too, but I am not sure of their accuracy or whether they are more like the freedom find option from skywatcher - a handy tool but not true encoders that can compensate for guiding in many cases. That AP900 is a lovely thing. Incidentally, I am not too hot on all the black and red, which is why I have powder blue counterweights! That mount gives you a solid base and futureproofs heavier scope or multiscope setups maybe.

Agree that you are in the close-enough territory. I asked earlier in the thread if you use the tilt adapter for the focuser, since that is one way to deal with the offset ghost in stars. your secondary might be fine and the relationship between the primary and the focuser could have a slight nudge. But that would mean checking all three again as they have a tight relationship. Not to worry if you have done that, but if you have the tilt adapter and have not done so, you might dial it in given you are able to get it this far with the collimation.

Lovely image and m15 is the interesting ting GC. As you said, theorised to have a black hole, and behaves as such from measurements. Big question in my mind is what is really at the centre of these ancient globular clusters.

Thank you Padraic

Good ideas. Here is what I see in a single 180 s sub of ngc 7822 where the moon just just about overhead and to the side. A reflection likely coming from that aluminium secondary holder. Blackening the screws is what I might do, at least to see where the secondary bright starburst comes from. I have not had an issues to change the springs in any of the mirror holders/cells, although the primary locks do shift collimation a lot, which I why I never tighten them. I have the main mirror collimation screws between half and full tension in collimation and it holds just fine. True, being able to strip and build is a great skill and glad to hear that it is performing well for you now. mind you, none of that should have happened in the first place really.

Thanks Dave, I read through all your trials and tribulations while researchign this scope as a quicker-to-get option vs a Tak 160. Your experience was one of the things I asked the contact at TS to check explicitly, along with collimation that involved making the secondary at least perfectly square to start out with - I can take care of the rest with tweaks. I got updated from the optical bench directly, which was very nice of them. I had issues with a couple of quad modified petzvals from them and they've ben very helpful and interactive with checking anything that I buy. Incidentally, sharpstar made those quads.... I notice a lot of starburst diffraction, testing to see where that comes from, as it partially disappears on stars towards the edge of the frames (giving an awful half starburst, half normal star), mapping the edges of the vignetting or the secondary mirror edge in the frame. there are 6 sets of 2 screw ends on the rim outside the primary cell, might be a culprit. I don't use ASI Air, having been using the sequencer capability in Sharpcap for deepsky for a while now and it is very good and very stable, so didn't go back to APT since. I used to use ASTAP, Fitswork and MixinDL some years ago for IR imaging and photometry with RC scopes, but found sharpcap (like many software options out there) quite good for an OSC imager.

Happy to, even if some are curious about how it performs to a degree. I had read lots of information on teething issues, and there are still some simple shortcomings I think Sharpstar could have taken care of. But, it is quite something to shift from f9 or f/6 to this.

Yes, I shot in the backgarden through LP and three LED streetlamps, just like this. A light you cannot see in this picture of my Mak-Newt (to the left) shines down, with another in the shot shining toward me. The only spot where I get the shadow intersection of the LED light 'venn diagram' prevents me from seeing polaris. I didn't use filters of any kind to see what data this scopes pulls in (especially considering the emission spectrum of the LEDs) and try to pick targets and position in the sky as much as I can. I used to live in the hills above macroom, basically bortle 2/3 with a full milky way every clear night in the spring and summer but I wasn't into visible spectrum imaging at the time. curious we are so close with somewhat similar setups. Your imaging setup and processing deliver very nice and naturally images too.

Thanks Richard. I think I will like it. The Tak 160ED is a great scope, and was what I had been saving for, but rare as hens teeth to get a hold of fast. The extender option to shift to galaxy imaging and its speed would make it an all rounder for me. But I do like this hypergraph 6 quite a bit. I am in Ballincollig.

Do you use a tilt adapter to which your focuser is attached?

Thanks Luke, appreciate that. So far so good I guess. I'm used to the tweak0need feeling though, from years on big RCs and my old favourite Mak-Newt. The collimation and focus stability from just the last 4 nights were comforting. Once I get past the honeymoon stage and tweaking, I might see what this can do with 8 hours exposure at f/2.8. A new psychology comes after moving from f/9 and f/6 to this - integration times of 2-4 hours don't feel like a finished image (but 3 hours here is theoretically 13.5 on the Mak-Newt!), but it gets really close which might be handy when good nights are separate be weeks

My bad. Can mods move this to imaging deepsky subforum please.

Just received the TS Hypergraph 6, the TS optics branded Sharpstar 15028 HNT. Hyperbolic mirror newtonian, 420 mm focal length, with 150 mm aperture, so F/2.8. Came packed very nicely, nothing was loose, shaky or otherwise as has been reported here and elsewhere, and has remained so since even with the scope coming in and out every night for the last 3 nights (we got lucky this week after so many weeks of clouds). It bodes well that this leap to fast scopes provided one of the best weeks of the year so far here.... Here is it mounted, a tidy size and easier than I expected to balance. Dovetail is narrower than standard losmandy, so I added a longer one with extra length adding needed rear-end weight. ASI2600 MC on board, with the black dot indicated the long side of the sensor that is top of frame. ZWO EAF added and focuser rotated to frame and balance. One con is the need for a large screw driver to get at an awkward place (3 of them) in order to rotate the focuser, so when M31 is imaged (soon hopefully) I hope the framing is OK. Not too keen rotating this focuser outside. A bobs knobs or captains wheel a la Takahashi would be useful here. Corrector is flush to its recommended depth, and using 55 mm backspacing for now. While extendable spacer and shims will take a week to arrive, I am imaging during this fine weather week regardless of the necessary tweaks, since I cannot get over the signal that comes from this scope in 180 s subs. The initial subs and stacks gave me a giddy feeling I must be honest, especially when there is room for improvement with small tweaks. Collimation done with cheshire and sight tube, after removing the corrector to get rid of diopter, but when that occurs it just gives two crosshairs either side of where the cross hair would be, much like a parallel line reticule, where the centre is the gap between the lines. Some fine tuning might be need one I change the spacing and tilt if its there. Onto some initial images. Must say, the psychology of 'does the newt need to be tweaked' is not there with this one, like it was my my Mak-Newt. Refractors almost never cause this 'worry', just plug and play. I look forward even more once I iron out the small niggly issue to get it best performance. Collimation is very stable so far, and so is the focus. I never had to change it yet. We will see what the winter is like. Image 1: Double cluster in Perseus 31 x 180 s subs (~1.5 hrs). ASI 2600MC Pro, -10C, Gain 0, native UV-IR cut filter on the camera. no processing apart from HLVG for green and a crop only after stretch in APP. All data processed in Astropixel Processor. Image 2: Collinder 399, coat hanger or Brocchi's cluster 31 x 180s subs (~1.5 hrs), -10C, Gain 0, same camera of course, HLVF only, as it came from APP. Image 3: Cocoon nebula IC 5146 77 x 180s subs (~4 hours), -10C, Gain 100 (where there is nebula involved, I am seeing what Gain 100 will do. Gain 0 seems to work very well for star clusters and brighter targets with 50k fwc giving wonderful star colors that I could never get before as easily as this anyway). This had some noise reduction, hlvg and matchcolor boost only, small adjustments compared to the stretched stack which also surprised me. I will be experimenting with sub length and gain in due course. Image 5 work-in-progress: NGC 7822 47 x 180s subs, -10C, Gain 100. This is a work in progress, to be continued tonight since I can image for 5 hours without meridian flip. About 20 frames were dropped last night due to moon reflections on the subs., leaving just 141 minutes integration. This is directly from APP after stretching, no processing yet. This is also ready showing detail and no filters were used, not even a light pollution filter, just the UV-IR cut of the camera even with LED light shining down. I am exciting about natural RGB imaging without even using quad band filters to give a nice tonal range in the reds/magentas/pinks that come without any processing. So, some tweaking to do with spacing to optimize, but I am very happy. I did notice a lot of 12 point diffraction flaring on brighter stars. You will notice that half of it disappears around some star, where it looks like a coma effect and reminiscent of flaring from mirror clips in some newts, but the reduction in flaring on one side of a star coincides exactly where the light intensity falls off where vignetting starts. I will reexamine once I have spacing perfect, because it is annoying in the way it affects star shapes. I do not mind the flaring, it add to the 'pizzazz' the fast newts give to images, but half-star flares are not nice. There are twelve bright screws around the mirror cell, which is one thing I must blacken just in case. Here is a picture of the top 6 screws around the mirror cell. They are flat ended and shiny, pointing up the light path. This one had issues with moonlight reflections in several of the frames, appearing as a green bright disc. I have made a nice light/dew shield form black yoga mat foam that is going to be used now. This scope is very sensitive to stray light reflections.

Thanks Wim. I cannot recall why I chose to try and image it, but I did measurements on it years ago in IR and maybe it was in the right part of the sky when planning what to image...images of it are rare enough, a few with longer focal length and a lot of very tight Ha data. Its much better in IR, and also in Ha if the image is very deep (as in Chile Atacama scope deep), where the Ha surrounds the galaxy for a huge region of space.

Thanks Padraic, similar situation. Even the first 2 hours were woefully dim and the image above is a crop to 50% of the whole frame area. Then something appear after 3 hours, a bit more after 4 but that took weeks with bits of clear sky. A case of 'I've come this far, I will do some more'. Had plans to go to 20 hours figuring some maths on the SNR, but added Ha because this week clear skies are full of moon. Cant remember when I looked up at the night sky when in dublin, but I guess you have light pollution in all directions?

Indeed, I know. Bias-calibrated darks did not make a perceptible change to my eyes. When I run short exposures and lots of them, with only periodic dithering every n-th sub, I do notice the benefit of bias-calibrated darks in nebula images at low gain, but longer exposures on this chip for me, with 15-20 pixel dithering between each sub, make the dark vs no-dark surprisingly similar at the whole image scale even when the bias persists. Its quite a leap compared from the asi1600 OSC chip, which was sometimes troublesome with flatdarks etc.

Darks rarely needed for the imx571 chip, and I tested with and without with no obvious difference from the library I made before finding out more about this system. Almost no electroluminescence glow and comparing darks with different gain and exposure is very different to most previous cmos generations. It's an interesting back illuminated cmos junction layout. There is a little more noise from the extracted ha from the osc compared to the rgb osc 4.2 hours data. H alpha from a mono cam would be nice. I might use the ha-o3 data from the filtered osc together as a mono luminance layer in this image someday as a comparison experiment.

This is the penultimate image from my Intes MN56 Maksutov Newtonian (127 mm / 762 mm). It is the dim but interesting galaxy IC 10, a very active starburst galaxy in our local group. You must image through the plane of the milky way. Somewhat similar to the small magellanic cloud but packed with Wolf-Rayet stars. I decided to stop at just over 8 hours data, which took 5 weeks due to the weather and an f/6 scope. This week (Aug 24-28) has great weather, but a full moon (and getting first light on another scope), so I called it a day for IC 10 for now. 4.2 hours OSC using ASI2600MC Pro, -10C, Gain 100, no filters aside from the UV-IC cut on the camera. Subs were 240 s. Stars as they are. I added 4 hours Ha data using altair quad band filter with the OSC. I extracted Ha (which is noisier than mono due to green and blue pixels ignored) and added the Ha stack with split RGB channels using Astropixel Processor. Gentle tweaks in PS CS5. Bortle 5/6 location with LED street lights pouring in to the backgarden. 15 px dither for every frame. Master flat used, no darks. This would be a great target for a f/5 longer focal length system, and Ha (7 nm or narrower), R, G and B filters with a mono camera. Still, I think it came out quite nice.

Basically what Vlaiv says, it tackles most points. One possibility to hone your skills and test what needs tweaking for longer subs and still get a target imaged, is to focus on star clusters or various types. right now, the double cluster in perseus (Caldwell 14) is a great option, not to near the moon, high enough and insensitive to the moon glow to some degree. Its direction is toward you Bortle 4 zone. Processing there, is more simlar to galaxies (stars and background anyway), which is always good practice and some of these clusters make great images when they get enough integration time. Same goes for Caroline's rose cluster and possibly (because it is interesting) the Sailboat cluster which has a nice dark nebula feature there too. Galaxies are a wash out at the moment, I am in the same situation myself. On a moonless night, the slightly wider band filters work great with OSC, such as the quad band filters. These keep Ha and SII, while having a 35 nm band pass for H-beta and OIII. It does improve emission nebula signal a lot, but wide enough to retain a lot of RGB star color and only take s small photometric color calibration to remove the small amount of redness form the stars.

I think this pier I have shown will take it no problem. I had considered the pier extension, but it is fairly short and the tripod legs still stick out, but you can measure it for 'extreme' dec and RA positions, especially if you let your mount go 15 degress past meridian for example. The long frac will never hit anything of my tri-pier which I why I took the punt on it. Glad I did if I ever have a long frac in the future I guess.

Ah, interesting. An array or rasa or other fast newtonians with adaptive optics could acquire a lot of data, deep, over big sky. Clever idea, especially when playing the filters. We used to do this with slow RCs to make up time, and they were good for IR imaging with slightly different camera sensors. Good luck with your setup.

Double RASA canon! Same optics and camera pixels, FOV, give you lots of near-identical options to mix RGB, mono, etc. I once saw a quad barrel setup, I think it was teh sharpstar 13028HNT. It had a nice idea to mount all four in a 2x2 single holder, probably only needed a single central mounting plate. How do you plan a mosiac with parallel optics? And can one scope be offset in DEC after initial platesolving to image two different targets while tracking in RA?

This is lovely, nicely done.